Hydrastar Electric Over Hydraulic Actuator Hums But Doesn't Run

Question:

Have this unit on my boat trailer. Unit has work perfectly for past 6 years. After a lay up of 6 weeks plugged in and pump unit only make a small humming sound as though no power coming through to make run. Have tested vehicle, battery and have plenty of juice to run unit. Can something inside unit be amiss. We haven,t bled anything yet.

asked by: Graham

Expert Reply:

It sounds like you are going to need to go through the basic testing procedure to determine where any problems might be on the HydraStar Electric-Hydraulic Actuator # HBA-12.

With the unit running and brake pressure applied, determine that a minimum of 8.5 volts DC are reaching the Hydrastar’s black wire.

Check to see if the white ground wire runs directly to the tow vehicle ground. IT MUST NOT BE GROUNDED TO THE TRAILER ONLY. IT IS IMPORTANT THAT THIS GROUND WIRE RUNS DIRECTLY TO THE TOW VEHICLE’S BATTERY GROUND. NO EXCEPTIONS.

Detach all wires from the Hydrastar leaving only the blue, black, white, and yellow or blue with white striped wires. It is important that the unit is disconnected from any other wires going to the towing vehicle or breakaway switch and breakaway battery. Failure to do so may result in a faulty test.

Using a 12 volt battery, connect the white wire to the negative terminal of the battery. Connect the black wire to the positive terminal of the battery. The motor should not run. If the motor runs, the unit needs repaired.

Leave the white wire connected to the negative terminal of the battery. Connect the blue and black wires together to the positive terminal of the battery. The motor should run and the unit should pressurize. If this does not occur, the unit needs repaired.

Leave the white wire connected to the negative terminal of the battery. Connect only the yellow or blue w/white striped wire to the positive terminal of the battery. The motor should run and the unit should pressurize. If this does not occur, the unit needs repaired.

If the unit checks OK, reconnect the wires leading to the trailer plug and repeat the tests. If you do not get the same results as before, the problem is in the trailer wiring or the electronic brake controller.